Introduction

The Microgate HDLC API implements high level support for link layer protocols such as LAPB and SNA SDLC. This support is visible to the application as a set of function calls and structure definitions. The portion of the API used for controlling the physical layer (hardware) is referred to as the base API. The base API is documented in the file HDLCAPI.CHM (Compiled HTML Help format).

Features

• Implements procedures of ISO4335 (data link) and ISO3309 (physical)
  
  
• Normal Response Mode (NRM) for SNA SDLC (half and full duplex)
  
  
• Asynchronous Balanced Mode (ABM) for LAPB and related protocols
  
  
• Multiple links on a single physical interface (Multidrop/LAPD)
  
  
• SDLC Loop Mode (UP/BCN/CFGR)
  
  
• Initialization Mode (SIM/RIM)
  
  
• XID support.
  
  
• Modulus 8 and 128 operation.
  
  
• Selective and multi-selective reject (SREJ) support.
  
  
• Address fields up to 16 bytes in length.

The following sections describe the terminology and concepts used by the API.